Package com.google.gwt.jsonp.client

Class JsonpRequestBuilder

  • public class JsonpRequestBuilder
extends java.lang.Object
    Class to send cross domain requests to an http server. The server will receive a request including a callback url parameter, which should be used to return the response as following: 
    <callback>(<json>);
    where <callback> is the url parameter (see setCallbackParam(String)), and <json> is the response to the request in json format. This will result on the client to call the corresponding AsyncCallback.onSuccess(Object) method.

    If needed, errors can be handled by a separate callback: 

    <failureCallback>(<error>);
    where <error> is a string containing an error message. This will result on the client to call the corresponding AsyncCallback.onFailure(Throwable) method. See setFailureCallbackParam(String).

    Example using JSON Google Calendar GData API: 

     String url = "http://www.google.com/calendar/feeds/developer-calendar@google.com/public/full" +
     "?alt=json-in-script";
 JsonpRequestBuilder jsonp = new JsonpRequestBuilder();
 jsonp.requestObject(url,
     new AsyncCallback<Feed>() {
       public void onFailure(Throwable throwable) {
         Log.severe("Error: " + throwable);
       }

       public void onSuccess(Feed feed) {
         JsArray<Entry> entries = feed.getEntries();
         for (int i = 0; i < entries.length(); i++) {
           Entry entry = entries.get(i);
           Log.info(entry.getTitle() +
                    " (" + entry.getWhere() + "): " +
                    entry.getStartTime() + " -> " +
                    entry.getEndTime());
         }
       }
     });
    This example uses these overlay types: 
     class Entry extends JavaScriptObject {
   protected Entry() {}

   public final native String getTitle() /*-{
     return this.title.$t;
   }-*/;

   public final native String getWhere() /*-{
     return this.gd$where[0].valueString;
   }-*/;

   public final native String getStartTime() /*-{
     return this.gd$when ? this.gd$when[0].startTime : null;
   }-*/;

   public final native String getEndTime() /*-{
     return this.gd$when ? this.gd$when[0].endTime : null;
   }-*/;
 }

 class Feed extends JavaScriptObject {
   protected Feed() {}

   public final native JsArray<Entry> getEntries() /*-{
     return this.feed.entry;
   }-*/;
 }

    • Constructor Detail

      • JsonpRequestBuilder

        public JsonpRequestBuilder()

    • Method Detail

      • getCallbackParam

        public java.lang.String getCallbackParam()
        Returns the name of the callback url parameter to send to the server. The default value is "callback".

      • getFailureCallbackParam

        public java.lang.String getFailureCallbackParam()
        Returns the name of the failure callback url parameter to send to the server. The default is null.

      • getTimeout

        public int getTimeout()
        Returns the expected timeout (ms) for this request.

      • requestBoolean

        public JsonpRequest<java.lang.Boolean> requestBoolean​(java.lang.String url,
                                                      AsyncCallback<java.lang.Boolean> callback)

      • requestDouble

        public JsonpRequest<java.lang.Double> requestDouble​(java.lang.String url,
                                                    AsyncCallback<java.lang.Double> callback)

      • requestInteger

        public JsonpRequest<java.lang.Integer> requestInteger​(java.lang.String url,
                                                      AsyncCallback<java.lang.Integer> callback)

      • requestObject

        public <T extends JavaScriptObject> JsonpRequest<T> requestObject​(java.lang.String url,
                                                                  AsyncCallback<T> callback)
        Sends a JSONP request and expects a JavaScript object as a result. The caller can either use JSONObject to parse it, or use a JavaScript overlay class.

      • requestString

        public JsonpRequest<java.lang.String> requestString​(java.lang.String url,
                                                    AsyncCallback<java.lang.String> callback)

      • send

        public void send​(java.lang.String url)
        Sends a JSONP request and does not expect any results.

      • send

        public JsonpRequest<java.lang.Void> send​(java.lang.String url,
                                         AsyncCallback<java.lang.Void> callback)
        Sends a JSONP request, does not expect any result, but still allows to be notified when the request has been executed on the server.

      • setCallbackParam

        public void setCallbackParam​(java.lang.String callbackParam)
        Parameters:
        callbackParam - The name of the callback url parameter to send to the server. The default value is "callback".

      • setFailureCallbackParam

        public void setFailureCallbackParam​(java.lang.String failureCallbackParam)
        Parameters:
        failureCallbackParam - The name of the failure callback url parameter to send to the server. The default is null.

      • setPredeterminedId

        public void setPredeterminedId​(java.lang.String id)

      • setTimeout

        public void setTimeout​(int timeout)
        Parameters:
        timeout - The expected timeout (ms) for this request. The default is 10s.